(void)walker

(void)walker is a toolbox for GDB which provides utilities for debugging software on an instruction level. It is heavily influenced by the gdbinit by mammon_, elaine, fG! et al. but opens up for a much more advanced solution by using Python instead of GDB commands.

Requirements

• GDB 7.5 or later built with support for Python extensions.
• FlowUI 0.2.1 or later.

Currently (void)walker has support for the following architectures, but adding new ones should be fairly easy at this point.

• X86
• X86-64
• MIPS

Installation

Install the requirements using pip:

pip install -r requirements.txt

Install (void)walker using the supplied setup.py by executing:

python setup.py install

Finally add the following line to your ~/.gdbinit to have it loaded automatically whenever GDB is launched:

python from voidwalker import voidwalker

The next time you start GDB you should see (void)walker being loaded.

You should also install all the (void)walker hooks in order to complete the integration with GDB.

Usage

Dumping the context of the current stack frame:

voidwalker context

Dumping data by specifying address and length:

voidwalker dump data <address> <length>

Dumping disassembly by specifying address and the number of instructions:

voidwalker dump instructions <address> <length>

Set a breakpoint at the start of the .text section. This command can be useful in setting a breakpoint at start if no symbols are available.

voidwalker gdb break text

The following commands can be used to patch the loaded binary. All modifications are applied on the loaded binary and the original file is never touched.

voidwalker patch snippet list
voidwalker patch snippet apply <name> <address>

Hooks

(void)walker commands that are prefixed with hook- are intended to be put into hooks of the same name in ~/.gdbinit, for example:

define hook-stop
    voidwalker hook-stop
end

Parameters

Changing themes:

voidwalker-theme

For instance, to set Zenburn as the default theme instead of Solarized add the following line to ~/.gdbinit:

set voidwalker-theme zenburn

Controlling what is shown as part of a context:

voidwalker-context-stackdw <number of doublewords>
voidwalker-context-instructions <number of instructions>

For instance, to suppress the stack from being dumped when calling voidwalker context add the following line to ~/.gdbinit:

set voidwalker-context-stackdw 0

Modifying what is performed when hooks are executed by GDB:

voidwalker-hook-context <on/off>

License

(void)walker is distributed under the GPLv3 license, the same as GDB. See the file called COPYING for the full license text.